The Fiat 850 is a small longitudinal

Longitudinal engine

In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back....

-rear-engined rear wheel drive car

Čar

Čar is a village in the municipality of Bujanovac, Serbia. According to the 2002 census, the town has a population of 296 people.-References:...

 which was produced between 1964 and 1973.
Its technical design was an evolution of the very successful Fiat 600

Fiat 600

The Fiat 600 is a city car produced by the Italian automaker Fiat from 1955 to 1969. Measuring only 3.22 m long, it was the first rear-engined Fiat and cost the equivalent of about € 6,700 or US$ 7300 in today's money . The total number produced from 1955 to 1969 at the Mirafiori...

. The internal name for the Fiat 600 development project was "Project 100" and consequently, the internal Fiat codename for the 850 project was 100G (G for the Italian word "grande" - big). The engine

Engine

An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...

 of the 850 was based on that of the Fiat 600, but had its capacity increased to 843 cc.